Molecular genetic prenatal diagnosis for a case of autosomal recessive spondylocostal dysostosis

Abstract

Autosomal recessive spondylocostal dysostosis type 1 (ARSCD1) is a member of the heterogeneous group of disorders termed the spondylocostal dysostoses that are characterized by multiple vertebral segmentation defects and rib anomalies. In these patients, the entire vertebral column is malformed and is replaced by multiple hemivertebrae giving rise to truncal shortening, abdominal protrusion and non-progressive spinal curvature. Genetic studies have shown that some cases of ARSCD are due to mutations in the somitogenesis gene, Delta-like 3 (DLL3), that encodes a ligand for the Notch signalling pathway-ARSCD type 1. To date, 17 different DLL3 gene mutations have been reported. A consanguineous family of Turkish origin with ARSCD type 1 due to a homozygous DLL3 mutation requested genetic prenatal diagnosis. Using DNA from a chorionic villus sample, both linkage analysis of the DLL3/19q region and direct sequencing for the familial mutation demonstrated that the unborn fetus was an unaffected carrier. This is the first case of molecular genetic prenatal diagnosis in any form of SCD.